Lubricating and penetrating oil



Nov. 27,1945. J. B. cALVA 2,389,508

LUBRI CATING AND PENETRATING OIL Filed Sept 15 1944' .OIO

024-6610 i2h1-l6'l8202224262830 o 5 no :5 2o as Percenc Cgclohexonone In rhe Lubricant B Patented Nov. 27, 1945 UNITED STATES WPATE'NT OFFICE 6 Claims.

.My invention relates to an improvement in lubricating oil, and deals more particularly with an oil including a relatively small percentage of a substance which will enhance the lubricating and penetrating qualities of the oil.

A penetrating oil to be efllcient must have two definite characteristics. In the first place, the oil must penetrate the spaces between the parts of a machine within the shortest possible time. In the second place, the oil must possess lubricating properties so as to reduce the friction between these parts. The first of these requirements immediately suggests that the addition of substances capable of reducing the viscosity of the oil and its surface tension to metallic surfaces is essential. The lubricating requirement immediately limits the choice of substances to be used either as lubricants; viscosity reducers, or surface tension reducers. Each one of these substances must fulfill certain essential requirements if it is to stay permanently in the machine. Each ingredient must be non-corrodingrhave low vapor tension, have good film forming properties, and have high film strength.

A lubricating oil should reduce as far as possible the coefllcient of friction between two relatively movable parts; hence, not only should such a lubricating oil have many of the properties mentioned above, but also it should have a tendency to permit movement between two relatively movable parts lubricated with the least amount of friction.

It is an object of the present invention to pro vide a penetrating oil including ingredients which meet the requirements above specified and which is capable of penetrating in the shortest possible time. This composition is so composed that the desirable qualities will remain after a considerable period of time and will not lose its penetrating qualities a short time after it has been used.

Penetrating oils have previously been formed embodying carbon tetrachloride as the added ingredient to reduce the viscosity and the surface tension of the oil to metallic surfaces. While such compounds are capable of accomplishing somewhat the desired result, I have found that because of the volatility of the carbon tetrachloride this material is likely to evaporate in a relatively short period of time, thus reducing the penetrating qualities of the oil. Furthermore, carbon tetrachloride is easily hydrolyzed and the hydrochloric acid thus produced has a corrodin effect on metallic surfaces.

It is an object of the present invention to provide a penetrating oil containing an ingredient such as cyclohexanone'as the means of reducing the viscosity and surface tension of oil to metallic surfaces. After considerable research, I have found that a suitable lubricant containing cyclohexanone will not only penetrate between metallic surfaces more quickly than any other compound with which I am familiar, but also this compoundwill continue its penetrating action continuously over a. period of time.

It is also an object of the present invention to provide a lubricating oil with oyclohexanone in order to enhance the lubricating properties of the oil. I have found that when a relatively minor amount of cyclohexanone is added to a lubricat ing oil the efficiency of the 011 both as a penetrant and as a lubricant is increased. My explanation for this fact is that the presence of cyclohexanone in a hydrocarbon oil of the type commonly used as a lubricant brings about a depolyme'rization of molecular a regates, thus increasing their freedom of motion and above all their ability to orientate themselves on polar surfaces such as those of metals.

Cyclohexanone thus plays a role in a hydrocarbon mixture similar to that of water in a solution of ionizable substances. If my theory is correct the presence of cyclohexanone in lubricating oils is beneficial for ,the reason that it facilitates the adsorption of the lubricating molecules on the surface of the metal and thus reduces and maintains a lower coemcient of friction between two relatively movable metallic surfaces coated with it.

Another object of the present invention is to provide a compound which may be added to oil and which is a strong solvent for polymerized products obtained by the cracking of lubricants. As a result gummy or semi-resinous products may be prevented from adhering to the moving parts of machinery. When this ingredient is used in penetrating oils, it also tends to dissolve gummy or resinous deposits. When added to a lubricant, it enhances the lubricating effect and prevents the precipitation of gummy or resinous materials.

It is a feature of the present invention that cyclohexanone when used in a suitable oil will not corrode or injure metal in any way. Cyclohexanone is non-corrosive and is non-acid. While carbon tetrachloride has a. tendency tochange to hydrochloric acid in the presence of moisture, my composition is entirely free of harmful ingredients. Actual tests have shown the product to be superior to penetrating oils embodying carbon tetrachloride, and this is particularly true where the metal surfaces become heated. Carbon tetrachlothose obtained when a higher percentage of cyclohexanone is employed.

These and other objects and novel features of my invention will be more clearly and fully set forth in the following specification and claims.

In the drawing forming a partof my tion:

Figure 1 is a chart showing the comparison of mechanical performance of a series of lubricants, some of which include cyclohexanone.

Figure 2 is a chart showing the effect of various percentages of cyclohexanone on the coefli- 'cient of friction.

when used as a pentrating oil, my formula in preferred form comprises pale paraflln oil, kerosene, and cyclohexanone. The percentages of kerosene used may vary, as may also the percentages of pale paraflln oil. The cyclohexanone may vary within certain limits, but when too little of this material is present in the compound, the penetrating qualities of the oil decrease. I have found that the percentage of cyclohexanone in' the mixture may vary from three to ninety percent, but is preferably approximately five percent by volume. When the percentage of cyclohexanone drops below approximately five per cent, the penetrating qualities of the oil decrease. Accordingly, when the oil is to be used for loosening frozen bolts and other metal parts frozen together, it is apparent that the cyclohexane can best be maintained at approximately five percent by volume of the oil.

of 80 to 100 viscosity at 100 F. It has a new test of 25 F. and a flash point of 365 F.

The foregoing formula defines the cyclohexanone content to be approximately five percent by volume of the product. Obviously if this oil is to be used as an additive product in the lubrication of motors and the like where on is already present in considerable volume the percentage of cyclohexanone may be increased substantially so that it will comprise the proper percentage of the entire body of oil. For example when the penetrating oil is added to lubricating oil used in the crank case of an internal combustion engine. the percentage of-cyclohexanone may be'materially increased so that its presence in the entire body of oil is more marked. When thus used, the kerosene may be absent.

I have found that when cyclohexanone is added to a lubricating oil, its presence will enhance the lubricating effect and prevent the precipitation of gummy or resinous matter on the surfaces being lubricated. When oils of higher viscosity are required, the kerosene may be absent, as the kerosene is required only in products particularly prepared for use as penetrating oils.

The following is a list of formulas of various penetrating oils which were used experimentally:

My preferred formula for penetrating oil is substantially as follows:

Per cent by volume Pale paraflin oil 75 Perfection kerosene 20 cyclohexanone 5 The pale paraflln oil used in the above formula has substantially the following properties:

Gravity 2830 B. (A. P. I.) Flash 285-300 F.

Fire 325-340 F. Viscosity 80-85 sec. at 100 F. Color Straw yellow The kerosene used in the preparation of my oil has approximately the following properties:

Density 425 B.

Flash 153 F.

Color (Saybolt for burning blush fluo- I rescein) #W A Pale of paraffin oil. B-Finol.

The following table discloses the results attained with various penetrating oils tested. In making these tests a number of bolts were thoroughly degreased, and nuts were tightened onto the bolts by hand. The bolts bearing the nuts were then submerged in a solution of ammonium chloride to provoke rapid corrosion. After a predetermined time, the bolts wer removed from the solution and tested by trying to turn the nuts by hand. The bolts were again replaced in the solution and allowed to remain until all of the nuts were frozen securely on the bolts. Tests showed that the freezing action of the nuts upon the bolts was substantially constant on the various bolts.

. A number of bolts were then subjected to each type of penetrating oil. From time to time after application of the penetrating oils it was attempted to remove the nuts from the bolts. In the following table Time in hours refers to the period of time which lapsed from the application of the oil to the testing of the bolt. The Number of bolts frozen refers to the total number of bolts that from the beginning of the test still remained frozen when tested with an eight inch wrench upon the bolts placed in a vise. Total number of bolts loosened records the total number of bolts loosened by the penetrating oil up to the time of the test. Ease of loosening evaluated as easy or hard as shown in the record by the letters E and H respectively refers to the observation made during loosening of the bolts as to whether the unscrewing 0f th nut was carried out with ease or with difilculty. When the letters E and H aseaoce are followed by a number in parentheses. this number represents the number of bolts about The "Numwhich the observation was made. her of applications of oil states the number of times oil was added to the bolts.

Number Number Number Time in Ease oi oi a plil 'ormula of bolts of bolts iroren loosened 100mm! 2% ga 0 10 0 l 1 10 0 v Commercial 8 8 2 E 2) 2 product A... 20 5 E 3;

30 4 o E l 0 0 l 10 0 G ommercial 8 7 3 product B.-. 4 t 2 8 0 10 0 1 l0 0 C ommercial 8 9 1 product 0... 20 8 2 30 5 5 0 10 0 l 10 0 C ommercial 8 10 0 product D.-. 20 7 3 30 4 6 0 6 0 1 6 0 0 ommercial 8 3 3 product E... 20 2 ,4 30 2 4 0 l0 0 I 1 10 0 Formula l. 8 7 3 E (2) 2 20 2 8 E (4) 30 0 10 H (2) 0 6 0 l l 6 0 Formula 2... 8 2 4 E (2) 2 2o 2 4 3O 2 4 0 l0 0 l 10 0 Formula 3..--- 8 7 3 i 20 4 6 30 3 7 0 10 0 1 l0 0 Formula 4-..-. 8 7 3 20 3 7 30 2 8 From the foregoing it is obvious that the use of cyclohexanone as an ingredient of penetrating oils and lubricating oils enhances considerably the penetrating and lubricating properties of the latter; this enhancing effect, I have found, in my experiments to exceed similar effects imparted by any of the other substances with which I am familiar. Not only does my penetrating oil loosen bolts more quickly than any other penetrating oil used with which I am familiar, but also the penetration continues more uniformly throughout a longer period of time. As a result it appears that the use of cyclohexanone in a penetrating oil is advantageous. Similarly, my lubricating oils containing cyclohexanone are far more efficient in their lubricating action because they have a stronger penetrating power between closely fitted surfaces at the same time that due to the strong solvent action of cyclohexanone, gummy or resinous-like substances are prevented from depositing on closely fitted moving parts, thus maintaining the free flowing of lubricant. essential to avoid the unnecessary wear of a machine.

The description above describes-the use of cyclohexanone in a penetrating oil, and deals particularly with the advantageous of this composition as a penetrant. I have found that cyclohexanone has very definite advantages when In order to determine the effect of various percentages of cyclohexanone in lubricating oil, experiments were made through the use of the Almen machine developed by the General Motors Corporation for the testing of high pressure lubricant. This machine includes a motor for driving a small journal at a constant speed in a split bearing. The bearing pressure on the journal may be increased at will by the addition of weights upon a scale beam operating a hydraulic system which transmits a greatly increased load to the bearing. With this machine a weight of two pounds added to the scale beam will produce a pressure on the projected area of the bearing of about one thousand pounds per square inch:

The lubricant to be tested is placed in a lubricant cup surrounding the bearing and journal, and the amount of oil used is Just enough to cover the journal. The machine includes a yoke which iswfree to swing at ninety degrees to the axis of the journal and as the friction between the journal and bearing increases the yoke deflects a proportional amount. This deflection is opposed by a second hydraulic system which operates an indicating gage calibrated in pounds per square inch. Thus the reading on the gage represents the frictional force developed between the journal and the bearing.

Since the energy consumed in overcoming the friction is dissipated in the form of heat an accurate knowledge of the temperature-viscosity relations of the lubricant being tested must be obtained. The temperature of the oil film in contact with the journal and the bearing was measured by means Of a precision potentiometer connected to a micro-thermocouple made of copper-constantan wires.

An .understanding of the relation between temperature and viscosity was obtained by means of Oswald-Fenske viscosity pipettes. As a slight variation in temperature introduces considerable error in the determination of viscosities, the thermostat bath was controlled by means of a precision thermoregulator operating, through a relay, a heating element immersed in the bath and connected in series with external variable resistance to keep the temperature of the bath constant within the limits of plus or minus 0.0l7 C. The tests were made by placing the oil to be tested in the cup of the Almen machine and the temperature of the oil and the cold junction of the thermocouple were noted. Two pound weights were added to the scale beam of the machine every 4 or 5 time interval. The temperature and the frictional force as read from the gage were recorded every fifteen seconds, which was the length of one time interval.

Two sets of experiments will be listed. In both of these tests a' lubricating oil of a well known make was used as a base. 'Various percentages of kerosene were added and the results tabulated. In the second series of tests various percentages of cyclohexanone were added to the same base oil and the results tabulated. From this information the charts shown in Figures 1 and 2 were prepared.

combined with a lubricant. I have also found that the percentage of cyclohexanone added to the lubricant has a very definite effect on the properties of the composition.

An examination of Figur 2 of the drawing shows the effect of cyclohexanone on the coefficient of friction of the lubricating oil. It will be noted from the curve indicated by the numeral ii] that when no cyclohexanone is used the coeflicient of friction is .015. As cyclohexanone is added the coefficient of friction drops sharply so that when but slightly over 1% of cyclohexanone is added the coefflcient of friction drops to .014. This reduction in the coefficient of friction continues until there is approximately 10% cyclohexanone in the mixture. Beyond this point an increase in the percentage of cyclohexanone brings about an increase in the coeillcient 01' friction. When 25% cyclohexanone is added to lubricating oil, the resulting mixture or composition has approximately the same coei'llcient of friction as the lubricating oil alone.

As a result of these tests it is obvious that when oil contains up to 25% cyclohexanone the result-- ant product has a lower coeflicient of friction than lubricating oil alone. For this reason I desire to confine my range of addition of cyclohexanone to approximately 25% From an observation of the curve I! it will be obvious that while up to 25% cyclohexanone in lubricating oil is advantageous, the preferred range will extend from about 3% to about 20%. I have also found that when used in combination with kerosene as a penetrating oil, the optimum percentage of cyclohexanone is about 5%.

Figure 1 shows another interesting effect of the addition of cyclohexanone to lubricating oil. In this graph the coefllcient of friction has been plotted against the dimensionless expression uN/P". This expression was introduced by the McKee brothers in 1929 and is reported in the Transactions of the American Society of Mechanical Engineers for 1929, pages 161-171.

The term u" is a measure of the kinematic viscosity in centistokes. This measurement was obtained by multiplying the time of flow of the oil in seconds at the corresponding temperatures by the calibration factor of the Oswald-Fenske pipette used. The McKee brothers on their experiments measured absolut viscosity of the oil in centipoises. In my opinion the difference in value of these two units does not alter the significance oi the results.

The term N equals the revolutions per minute of the shaft. The term P equals the'load per unit of projected bearing surface in pounds per squareinch and equals the total transverse load on the bearing, P divided by twice the radius of the journal times the length of the bearing.

Plotted against the dimensionless expression uN/P" is the coefficient of friction 1, which was obtained by dividing the friction moment by the applied load moment in pounds per square inch.

The curve II in Figure 1 shows the performance of No. 20W S. A. E. oil of a nationally advertised brand. It will be noted that the coefiicient of friction increases considerably as the value of the expression uN/P" increases. A bearing must be designed to compensate for an increased coeflicient of friction with an increase in speed, a change in the viscosity of the lubricant, a change in the load on the hearing, or a combination of these factors.

Curve 12 shows the variation in change of the coefficient of friction in the oil mentioned above when 5% kerosene has been added thereto. It will be noted that the coefficient of friction is high near the zero value of uN/P" and characteristically drops to a minimum at a relatively low value of this expression. The curve I2 follows the same general contour as the curve II, and it should be noted that the addition of a small amount of kerosene lowers the minimum value of the coefficient of friction.

The curve l3 shows the result of adding 20% of kerosene to the oil mentioned above. The curve is of the same general shape as the curves II and I2, the coemcient of friction increasing as the value of the expression 'uN/P" increases.

The curve I4 shows the effect of adding 5% cyclohexanone to the same base oil. It should be noted that the coemcien't of friction remains substantially equal upon an increase in the value 4 of the expression uN/P". This is an extremely.

important fact as it shows that the coefficient of friction does not increase upon changes in load, speed, or kinematic viscosity of the lubricant. Curve l5 shows the effect of the addition of 10% cyclohexanone to the same base oil. -Not only is the coefllcient of friction substantially reduced over that of the base oil used alone, but also the coeiilcient of friction actually decreases upon an increase in the value of the expression uN/P".

Curve I 6 shows the effect of the addition of 20% cyclohexanone to the base oil. This curve shows that even when 20% of the cyclohexanone is added, the coefllcient of friction remains substantially equal upon an increase in the value of the expression uN/P", but this coefllcient of friction is substantially greater than when but 10% of the additive is used.

The. unusual performance of lubricants containing cyclohexanone can be explained only by the fact that perhaps the presence of cyclohexanone in a hydrocarbon oil brings about a depolymerization of molecular aggregates normally present in the oil, thus freeing them to be adsorbed by orientation on the metallic surface. Tests show that when kerosene was added to the base oil the temperature of the mixture increased, whereas the addition of cyclohexanone to the base oil caused a decrease in temperature of the mixture. Thus the heat of solution of cyclohexanone in lubricating oil is positive which means that an increase in volume of the mixture is produced. This increase in volume can only be explained by the separation or breaking up of molecular aggregates.

As a result of the foregoing tests it appears that the use of up to 25% cyclohexanone as an addition r to lubricants will enable lubricating engineers to properly design bearings to operate at a predetermined temperature thus greatly assisting the engineers in proper design of the bearings. The tests also show that lubricants containing up to 25% cyclohexanone will be particularly advantageous in connection with machinery subjected to variable loads or variable speeds as well as to high speed machinery such as electrical motors, turbines and the like.

I have shown that cyclohexanone in a range of up to 25%, is not only desirable for use in a penetrating oil, but is also of value added to lubricating oil. Attempts have previously been made to use relatively high percentages of cyclohexanone in combination with a lesser percentage of lubricating oil, but I have found conclusively that such higher percentages produce a greater coeificient of friction than lubricating oil alone.

The present application is a continuation in part of my former application Serial No. 442,431, filed May 11, 1942 for Penetrating oil.

'In accordance with the patent statutes, I have described the principles of composition and operation of my penetrating and lubricating oil, and while I have endeavored to set forth the best embodiments thereof, I desire to have it understood that obvious changes may be made within the scope of the following claims without departing from the spirit of my invention.

I claim: 1. A lubricating substance containing in its cyclohexnnone but in sumcient quantity to reduce the coeiiicient of friction.

4. A penetnting oil including as essential in- 10 gredients lubricating oil. kerosene, and 3 to 20% cyclohexi'mone. I

. 5. A penetrating oil including as essential ingredients lubricating oil, kerosene and substantially 5% cycloliexenone,

6. A penetrating 011 comprising. lubricating oil,

' substantially 20% kerosene and substantially 5% cyclohexanone.

JOSE B. CALVA. 

